Django GenericFKAdmin

Using GenericForeignKey in your Django models is cool, the default behavior of Django Admin is not. This package allows you to replace the content_type and object_id fields in your admin forms with a single input that is prefilled with only the models related through GenericRelation fields.

Setup

Install

pip install django-genfkadmin

uv add django-genfkadmin

Usage

Using this package is pretty simple.

1. Create a subclass of GenericFKModelForm for your model.
2. Create a subclass of GenericFKAdmin for your model.
3. ???
4. Profit!

e.g. in your admin.py

from genfkadmin.admin import GenericFKAdmin


@admin.register(Pet)
class PetAdmin(GenericFKAdmin):
    pass

Providing a filter_callback

If you want to further filter the queryset (perhaps by something related to the parent instance of your model with GenericForeignKey) you can define a method on your admin class as follows:

@admin.register(MarketingMaterial)
class MarketingMaterialAdmin(GenericFKAdmin):

    def filter_callback(
        self,
        queryset: QuerySet,
        obj: MarketingMaterial | None = None,
    ):
        if obj:
            return queryset.filter(customer=obj.customer)
        return queryset

Now when loading an existing MarketingMaterial, the content_object options are filtered by the chosen Customer

Using GFK Resolved Values

You might want to utilize the object of the GenericForeignKey field somewhere in your form code, such as your clean method. To do this use the get_generic_field_name_for method.

class GenreAdminForm(GenericFKModelForm):

    class Meta:
        model = Genre
        fields = "__all__"

    def clean(self):
        super().clean()
        media_generic_field = self.get_generic_field_name_for("media")
        media = self.cleaned_data[media_generic_field]
        if media.name.lower() != media.name:
            raise ValidationError({media_generic_field: "media name must be lowercase"})
        return self.cleaned_data

A complete example django app exists in this repository at here